Disengageable electrical circuit connector



R. C. MARHOLZ March 23, 1948.

DISENGAGEABLE ELECTRICAL CIRCUIT CONNECTOR 4 Sheets-Sheet 1 Filed July 21, 1944 March 23, 1948. R. c. MARHOLZ 2,438,371

DISENGAGEABLE ELECTRICAL CIRCUIT- CONNECTOR Filed July 21, 1944 4 Sheets-Sheet 2 22m raw/25 2 2?" a 81/?4JA;

March 23, 194%). R g, MARHQLZ 2,438,373

DISENGAGEABLE ELECTRICAL CIRCUIT CONNECTOR Filed July 21, 1944 4 Shasta-Sheet 3 mil/EN 01a.

Marcia 23 1948.

R. C. MARHCDLZ DISENGAGEABLE ELECTRICAL CIRCUIT CONNECTOR Filed July 21, 1944 4 Sheets-Sheet 4 I N VEN TOR.

Patented Mar. 23, 1948 DISENGAGEABLE ELECTRICAL CIRCUIT CONNECTOR Richard C. Marholz, Chicago, 111.,

mesne Illlgnments, to Belmont Radio Co auignor, by

tion, Chicago, 11]., a corporation of Illinois Application July 21, 1944, Serial No. 545,911 4 Claims. (Cl. 173-328) This invention relates to a disengageable electrical circuit connector of the full-floating contact type and. while it is of general application, it is particularly adaptable for application in a disconnectible plug and socket and will be described as embodied in such an application.

In many applications ofdisconnectible electrical plugs and sockets it is required that the complementary contact elements maintain a good electrical contact in spite of minor misalignments due to either manufacturing tolerances or to slight misalignments of the electrical apparatus with which the plugs and the sockets are associated. For example, in certain types of communication and control apparatus of complicated forms, the apparatus is constructed in the form of a chassis rack: that is, it is divided into a number of sub-assembly units or chassis and these chassis are removably mounted in a rack or cabinet much in the manner of a series of drawers in a chest, usually with the sockets mounted on the back of the rack and the plugs attached to the back of the chassis and adapted to engage the sockets when the chassis is fully inserted. This arrangement has a number of advantages in that, when the chassis is withdrawn for service or repair, it avoids numerous circuit changes and also usually breaks the connection of the circuit embodied in the chassis from the supply circuit, thereby removing theshock hazard to the operator.

It is, of course, difllcult in such a unit construction to maintain the precise alignmentmf the mechanical parts necessary to ensure good electrical contacts from rigid-contact plug and socket connectors, so that it has been proposed to utilize full-floating-contact type connectors, that is, connectors of the type in which the contact elements are freely disposed in recesses in the connectors without any fixed engagement with the body of the connector, permitting limited movement of the contact elements in any direction. In some of these proposed connector constructions, the arrangement of the contact elements and parts is such that manufacturing tolerances on the individual elements are cumulative in the final structure, thus introducing difficult alignment problems. In this type or plug and socket connector, either of the rigid-contact typ or the full-floating-contact type, the structures previously proposed have tended to apply excessive lateral strains upon the contact elements in case of any substantial misalignment of the plug and socket occasioned by inaccuracies of the mechanical structure of the rack and chassis units. These stresses in some instances have deformed the contact elements or chipped or broken the insulating material comprising the supporting body of the plug or socket, thus aggravating the diiliculty upon subsequent engagements of the plug and socket.

It is an object of the invention. therefore, to

provide a new and improved disengageable electrical circuit connnector of the full-floating-contact type which is eflective to overcome one or more of the disadvantages of the prior art arrangements.

It is another object of the invention to provide a new and improved disengageable electrical circuit connector of the full-floating-contact type which is particularly adapted for use in plug and socket connectors suitable for the unit type of rack and chassis construction of electrical apparatus.

It is another object of the invention to provide a new and improved disengasea'ble electrical circuit connector of the full-floating-contact type which is simple and economical in construction and in which the effects of manufacturing tolerances on the individual elements are not cumuiative but random.

It is another object of the invention to provide a new and improved disengageable electrical circuit connector of the full-floating-contact type for use in plug and socket connectors by means of which the lateral strains of the contact elements may be substantially removed.

In accordance with the invention, a disengageable electrical circuit connector of the full-floating-contact type comprises a pair of complementary wafers-of insulation material, each of the wafers being formed with one or more recesses, and means for clamping the wafers in opposed relation with corresponding recesses in alignment. The connector includes an elongated contact element freely disposed in each of one or more selected pairs of aligned recesses in the wafers and positioned thereby, the clamping means being eflective substantially parallel to the contact elements and the wafers, when clamped by the means, including provisions for engaging and retaining the elements while permitting limited motionthereof.

Further in accordance with the invention, a disengageable electrical circuit connector of the full-floating-contact type comprises a pair of wafers of insulation material, means for clamping the wafers in opposed relation, at least one of the wafers being formed with one or more tioned thereby. The insulation wafers, when clamped by the means, include provisions for engaging and retaining the contact elements while permitting limited motion thereof. The connector also includes a rigid, integral, supporting frame independent of the clamping means and means for securing the wafer and contact elements assembly, when clamped, to the frame. Preferably in a connector ofthis type the frame includes provisions for laterally positioning the wafers independently of the clamping means.

Further in accordance with the invention a disengageable electrical plug and socket embodies a connector of the full-floatlng-contact type described in any of the preceding paragraphs and the plug and socket include. complementary aligning elements proportioned to engage each other before engagement of their associated contact elements.

For a better understanding of the invention, together with other and further objects thereof, reference is had to the following description taken in connection with the accompanying drawings while its scope will be pointed out in the appended claims.

Referring now to the drawings,

Figs. 1a and 1b are top and side views, respectively, the latter partly in exploded section, of a disengageable electrical connector of the plug type embodying the invention;

Figs. 2a and 2b are similar views of a disengageable electrical connector of the socket type embodying the invention and adapted to receive the plug of Figs. 1a. and 1b;

Fig. 3 is an enlarged end view, partly in section, of the, plug and socket connector of Figs. 1a, 1b and 2a, 2b in the proper relation just prior to engagement of the contact elements;

Fig. 4 is a perspective view, partially schematic of a chassis rack embodying the disengageable electrical connector of the invention, while Fig. 5 is a cross-sectional detail of a portion of the rack of Fig. 4 along the line 5-5.

Referring now to Figs. la, 1b of the drawings, there is illustrated a disengageable electrical connector of the full-floating contact type adapted to be used-as a disengageable plug. The plug of Figs. 1a, 112 comprises two pairs of complementary wafers I0, III and II, II of insulation material, preferably of a molded ceramic material. The wafers I0 and II are of rectangular shape and are formed with upturned rims Illa, IIa terminating at the corners in pedestals IIlb, IIb. At least one of each of the pairs of wafers II), II, preferably both, are formed with one or more recesses IIlc, IIc (Fig. 3) preferably regularly spaced inone or more parallel rows as indicated in Fig. 1a. Each of the recesses is shown as comprising a generally conical depression in the outer face of one of the wafers I0 and II and a substantially cylindrical recess in the inner face of the wafer, joined by a narrow rectangular aperture. However, these recesses may, take any of a variety of shapes in accordance" with the particular design of the connector and these recessed portions are collectively referred to herein as the recesses in the insulation wafers.

The connector also includes means for clamping the wafers in opposed relation, this means comprising the depressions Ind, I Id at each of the corners of the wafers at which are located the holes IIle, Me for receiving bolts I2. The connector also includes a plurality of contact ele- 4 me'nts I3, one being disposed freely in each of one or more selected recesses of one of the wafers or, in the embodiment illustrated, in selected pairs of aligned recesses I00, He in the wafers and positioned by such recesses. The contact elements I3 are provided with enlarged middle sections I3a having shoulders lab.

The connector also includes a supporting .frame I4 for the wafer and contact assembly.

when clamped in their normal positions, and this supporting frame is preferably a rigid integral structure, as illustrated, which is independent of, that is, forms no part of, the clamping means of the connector. The frame I4 includes provisions for positioning the wafer and contact assembly laterally independently of the clamp ing means, these provisions comprising the opening Ida proportioned closely to surround the periphery of the wafers I0 and II when in their clamped position. The frame I4 is formed with an internal peripheral rib I Ib, the opposed wafers I0 and II in their normal positions being clamped with the pedestals IIlb, IIb engaging opposite faces of the rim Mb. The pedestals vIllb, I lb can be ground or otherwise finished to ensure an accurate spacing and positioning of the wafers I0 and II in the frame I4.

With the arrangement described, when the opposing wafers I0 and II are clamped by the bolts I2 to engage opposite faces of the rim Mb, the clamping means is effective substantially parallel to the contact elements I3b, which are full-floating, so that the pressure of the clamping means exerts no stress on the contact elements I3 nor on the wafers II), II in a direction normal to the contact elements I3, which stress might tend to displace them laterally and impair their alignment with corresponding elements of the associated socket described hereinafter. As can be seen from Fig. lb and Fig. 3, the wafers III- and II, when clamped, include provisions, for engaging and retaining the contact elements I3 while permitting limited 'motion thereof, these provisions being either the inner surfaces of the opposed wafers I0 and II or the inner surfaces of the corresponding recesses Illc, IIc which en gage the shoulders I3b of the enlarged central portions I3a, of the contact elements and limit longitudinal movement thereof. Conversely, if desired, these provisions may comprise protrusions formed on the wafers I0, I I engaging complementary recesses formed in the contact ele- In, the plug type of connector of Figs. la, 1b, the ends I30 of the contact elements I3, which in use are remote from the associated socket, extend through their respective recesses I00 of the upper wafer II] to provide means for making an external electrical connection thereto. Similarly, the other ends, I311 of thecontact elements I3 which,

when associated with a complementary socket,

form elements of resilient frictional contacts, ex-

tend through the recesses of the wafer II for insertion in the complementary socket.

As illustrated in Figs. 1a., 1b, duplicate wafer and contact assemblies are disposed side by side in the frame I4, the wafers and contact elements of the duplicate assemblies being identified by similar reference numerals, but not requiring a repeated description. It will be apparent that any desired number of duplicate Wafer contact element assemblies may be mounted within a single supporting frame.

Referring now to Figs. 2a and 2b, there are represented a disengageable electrical connector of 5 the socket type suitable for operation with the plug of Figs. la, 1b. The elements of the socket connector of Figs. 2a and 2b, with the sole exception of the contact elements, are substantially 7 identical withthose of Figs. la, 1b and for the sake of clarity corresponding elements are identified by the same reference numerals. In the connector of Figs. 2a, 21) each of the contact elements I5 is in the form of a strip of resilient conductive material, such as brass, bent double on itself with re-entrant portions I5a (Fig. 3) constructed to form a spring clip for receiving the protruding portions I3d of the contact elements I3 of the plug of Figs. la, lb. One end I5d of each of the contact elements I5 extends through a recess Illc of its associated wafer III, while the spring clip portion I5a thereof is in alignment with a recess I Io in the wafter I I to facilitate the entry of the contact elements I3 of the plug connector of Figs. 1a, lb; The contact elements I5 are formed with outwardly flaring shoulders I51) near their middle section, these shoulders engaging the inner face of the wafer I or the bottoms of the inner recesses IIIc thereof while the other ends of the elements I fit into and engage the inner faces of the cylindrical recesses lie of the inner face of the other wafer II.

' From the description of Figs. 1a, lb and 2a, 2b it will be seen that the insulation wafers I0 and I I are completely interchangeable, both as between the opposing wafers of each of the types of connectors and as between the plug and socket connectors. This has the apparent advantage of reducing the number of types of molded insulation elements required.

The supporting frame I4 of the plug connector of Figs. 1a. lb and the frame I4 of the socket connector of Figs. 2a, 2b include provisions to ensure their proper alignment when brought into engagement before the engagement of their associated contact elements. Specifically. the frame I4 of the plug connector of Figs. 1a, 1b is provided with a circular socket or hole I40 at each end thereof while the frame of the socket connector of Figs. 2a, 2b is provided with a complementary pin I4d at either end thereof having a tapered end portion Me to facilitate entry into the sockets Me of the complementary connector.

As indicated in the enlarged detail view of Fig. 3, the length of the pins Md is such that they enter the sockets I40 of the plug connector, during the engagement of the plug and socket, prior to the engagement of the contact elements I3 of the plug with the spring contacts of the socket and even prior to the entry of the contact elements i3 into the slot-like recesses or apertures @Ic of the wafer ll of the socket connector. By this arrangement the engagement of the plug and socket are facilitated in that any minor misalignments of the plug and socket due to manufacturing tolerances or to inaccuracies of their mountings in the chassis and rack portions of the associated electrical apparatus are taken up by the pins Md and sockets i 10. Thus, the maximum possible accuracy of alignment is assured before it is attempted to force the plug and socket into engagement. This is particularly helpful when the plug and socket connectors include a large number of contact elements requiring a considerable force to effect their engagement. At the same time the rigid supporting frames I4 and sturdy pins I ld and sockets I40 absorb any lateral strains or shocks imposed upon the plug and socket connectors either during their engagement or thereafter in the normal operation of the apparatus of which they form a part. This avoids deformation of the contact elements of the connectors, which would increase the difficulty of subsequent engagement and disengagement of the plug and socket, and also substantially eliminates strains on the insulation wafers I0 and I I. In the case of the use of molded ceramic material for the wafers I0 and II, which is brittle, the described aligning means avoids substantial lateral stresses and strains which might crack or chip the wafers. particularly at the recesses I00, I Ic or at the holes I06, I I c for the clamping bolts.

Referring now to Fig. 4, there is represented an electrical chassis rack including a housing or cabinet 20 in which are removably mounted a plurality of electrical apparatus chassis, such as the chassis illustrated at II, the chassis being disposed one above the other in vertical alignment like the drawers in a chest. The cabinet 20 is provided with a vertical inset cable duct 20a the back of which is in the form of an apertured supporting plate. A disengageable plug and socket of the type described is provided for each of the chassis 2| and comprises complementary plug and socket members, corresponding ones of which are adapted to be mounted on the supporting plate of the cable duct 20a and the others being adapted to be individually mounted on the chassis. As illustrated. a series of sockets 22 are mounted on the back plate of the duct 20a while a complementary plug 23 is mounted on the back of each of the chassis 2|. The details of the mounting of the sockets 22 on the back plate Zilb of the cable duct 20a is shown in Fig. 5, the plate 20b being provided with a series of large apertures to permit access I to the contact terminals I5a of the socket 22.

The plate 20b is also provided with appropriately spaced apertures 200 for receiving a plurality of machine screws 24 under the head of each of which is inserted a spring washer 25. The details of the mounting of the socket from the back plate 201) are shown more clearly in Fig. 3. As there illustrated each of the screws 24 is formed with an enlarged shank 24a which engages the frame i4 of the associated socket. The shank has a diameter substantially less than that of the apertures 20c and a length substantially greater than the thickness of the back plate 201), whereby the sockets 22 have a limited free transverse movement with respect to the backing plate.

20b and are resiliently supported therefrom in a free-floating connection. The several sockets 22 may be interconnected by suitable electrical cables 26, whereupon a removable cover plate 2? may be secured to cover the cable duct 20a.

It will be apparent that, upon the insertion of any of the chassis 2! into the cabinet 20, the complementary socket 22 and plug 23 associated with such chassis will be brought into engagement. As described above, the aligning pins lid and socket 540 preliminarily align the plugs and sockets and absorb any lateral strains due to misalignment of the chassis. At the same time the resilient or free mounting of the socket frames it on the back plate 20b of the cable duct 20a permits limited transverse movement of the sockets to accommodate inaccuracies in alignment of the chassis with the rack or cabinet 20.

While there has been described what is at present considered to be the preferred embodiment oi the invention, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit or scope of the invention.

I claim:

1. A disengageable electrical circuit connector including in combination an open frame, an internal rib within said frame, a pair of complementary opposed wafers of insulation material positioned within said open frame on opposite sides of said internal rib and each having a plurality of recesses oppositely positioned and each pair of opposed recesses providing a cavity therebetween, contact means in each pair of recesses having a portion in the cavity dimensioned for floating movement therein as limited by the walls of such recesses, said contact means having another portion extending out of a wafer for receiving a circuit connection thereto, and fastening means through said wafers to clamp the pair of wafers toward one another against the internal rib, said wafers being maintained rigid in the frame but each said contact means floating within limits in the wafers.

2. A disengageable electrical circuit connector including in combination a frame comprising an outer rim with top and bottom faces and open centrally thereof, an internal rib within said frame extending parallel to said faces and between the same, a pair of complementary opposed wafers of insulation material each having a plurality of recesses therein and said pair being positioned within said open frame supported on opposite sides of said internal rib with said recesses oppositely positioned and each pair of opposed recesses providing a cavity therebetween, contact means in each pair of recesses having a. portion positioned in the cavity dimensioned for floating movement within the cavity as limited by the walls of such recesses, said contact means having at least one portion extending out of a wafer for receiving a .circuit connection thereto, and fastening means extending through 3. In a connector as defined in claim 1 wherein said contact means comprises a metal member and said portion in said cavity comprises an enlargement engageable with the walls of said recesses.

4. In a connector as defined in claim 1 wherein said contact means comprises a metal member and said portion in said cavity comprises resilient prong receiving means with a bend at one end and a shoulder at the other end engageable with the walls of said recesses.

RICHARD C. MARHOLZ.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,157,026 Mesohenmoser Oct. 19, 1915 1,227,375 Boirault May 22, 1917 1,418,171 Raettig May 30, 1922 1,686,534 Rosenzweig Oct. 9, 1928 1,722,816 Meunier July 30, 1929 1,750,014 Lofgren Mar. 11, 1930 2,031,564 Knutson Feb. 18, 1936 2,124,182 Braun July 19, 1938 2,135,267 Alden Nov. 1, 1938 2,151,756 Fletcher et al Mar. 28, 1939 2,162,453 Field June 13, 1939 2,173,323 Roby Sept. 19, 1939 2,207,477 Blackmon July 9, 1940 2,274,422 Mahoney et al Feb. 24, 1942 FOREIGN PATENTS 4,0 Number Country Date 381,178 Great Britain 1932 

